/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.tools;

import org.apache.iotdb.db.exception.TsFileTimeseriesMetadataException;
import org.apache.iotdb.tsfile.exception.TsFileStatisticsMistakesException;
import org.apache.iotdb.tsfile.file.metadata.MetadataIndexEntry;
import org.apache.iotdb.tsfile.file.metadata.MetadataIndexNode;
import org.apache.iotdb.tsfile.file.metadata.TimeseriesMetadata;
import org.apache.iotdb.tsfile.file.metadata.enums.MetadataIndexNodeType;
import org.apache.iotdb.tsfile.read.TsFileSequenceReader;
import org.apache.iotdb.tsfile.read.common.Path;
import org.apache.iotdb.tsfile.utils.Pair;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.nio.BufferOverflowException;
import java.nio.ByteBuffer;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

public class TsFileSelfCheckTool {

    private static final Logger logger = LoggerFactory.getLogger(TsFileSelfCheckTool.class);

    private Map<Long, Pair<Path, TimeseriesMetadata>> getTimeseriesMetadataMapWithReader(
            TsFileSelfCheckToolReader reader) throws Exception {
        Map<Long, Pair<Path, TimeseriesMetadata>> timeseriesMetadataMap = null;
        timeseriesMetadataMap = reader.getAllTimeseriesMetadataWithOffset();
        return timeseriesMetadataMap;
    }

    public Map<Long, Pair<Path, TimeseriesMetadata>> getTimeseriesMetadataMapWithPath(String filename)
            throws IOException, TsFileTimeseriesMetadataException {
        TsFileSelfCheckToolReader reader = new TsFileSelfCheckToolReader(filename);
        Map<Long, Pair<Path, TimeseriesMetadata>> timeseriesMetadataMap = null;
        try {
            timeseriesMetadataMap = getTimeseriesMetadataMapWithReader(reader);
        } catch (Exception e) {
            logger.error("Error occurred while getting all TimeseriesMetadata with offset in TsFile.");
            throw new TsFileTimeseriesMetadataException(
                    "Error occurred while getting all TimeseriesMetadata with offset in TsFile.");
        }
        return timeseriesMetadataMap;
    }

    /**
     * @param filename   The path of TsFile.
     * @param fastFinish If true, the method will only check the format of head (Magic String TsFile,
     *                   Version Number) and tail (Magic String TsFile) of TsFile.
     * @return There are four return values of the check method. The return value is 0, which means
     * that the TsFile self check is error-free. The return value is -1, which means that TsFile
     * has inconsistencies in Statistics. There will be two specific exceptions, one is that the
     * Statistics of TimeSeriesMetadata is inconsistent with the Statistics of the aggregated
     * statistics of ChunkMetadata. The other is that the Statistics of ChunkMetadata is
     * inconsistent with the Statistics of Page aggregation statistics in the Chunk indexed by it.
     * The return value is -2, which means that the TsFile version is not compatible. The return
     * value is -3, which means that the TsFile file does not exist in the given path.
     */
    public long check(String filename, boolean fastFinish)
            throws IOException, TsFileStatisticsMistakesException, TsFileTimeseriesMetadataException {
        logger.info("file path: " + filename);
        TsFileSelfCheckToolReader reader = new TsFileSelfCheckToolReader(filename);
        Map<Long, Pair<Path, TimeseriesMetadata>> timeseriesMetadataMap = null;
        long res = -1;
        try {
            timeseriesMetadataMap = getTimeseriesMetadataMapWithReader(reader);
            res = reader.selfCheckWithInfo(filename, fastFinish, timeseriesMetadataMap);
        } catch (TsFileStatisticsMistakesException e) {
            throw e;
        } catch (Exception e) {
            logger.error("Error occurred while getting all TimeseriesMetadata with offset in TsFile.");
            throw new TsFileTimeseriesMetadataException(
                    "Error occurred while getting all TimeseriesMetadata with offset in TsFile.");
        } finally {
            reader.close();
        }
        return res;
    }

    private class TsFileSelfCheckToolReader extends TsFileSequenceReader {
        public TsFileSelfCheckToolReader(String file) throws IOException {
            super(file);
        }

        /**
         * Traverse the metadata index from MetadataIndexEntry to get TimeseriesMetadatas
         *
         * @param metadataIndex         MetadataIndexEntry
         * @param buffer                byte buffer
         * @param deviceId              String
         * @param timeseriesMetadataMap map: deviceId -> timeseriesMetadata list
         * @param needChunkMetadata     deserialize chunk metadata list or not
         */
        private void generateMetadataIndexWithOffset(
                long startOffset,
                MetadataIndexEntry metadataIndex,
                ByteBuffer buffer,
                String deviceId,
                MetadataIndexNodeType type,
                Map<Long, Pair<Path, TimeseriesMetadata>> timeseriesMetadataMap,
                boolean needChunkMetadata)
                throws IOException {
            try {
                if (type.equals(MetadataIndexNodeType.LEAF_MEASUREMENT)) {
                    while (buffer.hasRemaining()) {
                        long pos = startOffset + buffer.position();
                        TimeseriesMetadata timeseriesMetadata =
                                TimeseriesMetadata.deserializeFrom(buffer, needChunkMetadata);
                        timeseriesMetadataMap.put(
                                pos,
                                new Pair<>(
                                        new Path(deviceId, timeseriesMetadata.getMeasurementId(), true),
                                        timeseriesMetadata));
                    }
                } else {
                    // deviceId should be determined by LEAF_DEVICE node
                    if (type.equals(MetadataIndexNodeType.LEAF_DEVICE)) {
                        deviceId = metadataIndex.getName();
                    }
                    MetadataIndexNode metadataIndexNode = MetadataIndexNode.deserializeFrom(buffer);
                    int metadataIndexListSize = metadataIndexNode.getChildren().size();
                    for (int i = 0; i < metadataIndexListSize; i++) {
                        long endOffset = metadataIndexNode.getEndOffset();
                        if (i != metadataIndexListSize - 1) {
                            endOffset = metadataIndexNode.getChildren().get(i + 1).getOffset();
                        }
                        ByteBuffer nextBuffer =
                                readData(metadataIndexNode.getChildren().get(i).getOffset(), endOffset);
                        generateMetadataIndexWithOffset(
                                metadataIndexNode.getChildren().get(i).getOffset(),
                                metadataIndexNode.getChildren().get(i),
                                nextBuffer,
                                deviceId,
                                metadataIndexNode.getNodeType(),
                                timeseriesMetadataMap,
                                needChunkMetadata);
                    }
                }
            } catch (BufferOverflowException e) {
                throw e;
            }
        }

        public Map<Long, Pair<Path, TimeseriesMetadata>> getAllTimeseriesMetadataWithOffset()
                throws IOException {
            if (tsFileMetaData == null) {
                readFileMetadata();
            }
            MetadataIndexNode metadataIndexNode = tsFileMetaData.getMetadataIndex();
            Map<Long, Pair<Path, TimeseriesMetadata>> timeseriesMetadataMap = new TreeMap<>();
            List<MetadataIndexEntry> metadataIndexEntryList = metadataIndexNode.getChildren();
            for (int i = 0; i < metadataIndexEntryList.size(); i++) {
                MetadataIndexEntry metadataIndexEntry = metadataIndexEntryList.get(i);
                long endOffset = tsFileMetaData.getMetadataIndex().getEndOffset();
                if (i != metadataIndexEntryList.size() - 1) {
                    endOffset = metadataIndexEntryList.get(i + 1).getOffset();
                }
                ByteBuffer buffer = readData(metadataIndexEntry.getOffset(), endOffset);
                generateMetadataIndexWithOffset(
                        metadataIndexEntry.getOffset(),
                        metadataIndexEntry,
                        buffer,
                        null,
                        metadataIndexNode.getNodeType(),
                        timeseriesMetadataMap,
                        false);
            }
            return timeseriesMetadataMap;
        }
    }
}
